We propose to continue our research on the control of RNA synthesis and the mechanisms of RNA processing. Our work will exploit the new techniques of restriction endonuclease mapping of DNA, cloning of DNA and DNA sequence analysis. In the area of tRNA biosynthesis we plan to continue our work on the bacteriophage T4 tRNA's and to extend this work to a study of the biosynthesis of E. coli and yeast tRNA. In order to obtain a greater understanding of promoter and operator structures we plan to determine the sequence of the control region of the biotin gene cluster in E. coli. We will initiate work on the nucleotide sequence of the histone gene cluster in Drosophila in order to study the control of gene expression in eukaryotes.